Mohamed Mamadouh 20, appears in court with his attorney for arraignment,Thursday, May 12, 2011, in New York. Mamdouh and Ahmed Ferhani, 26, are charged with a terrorist plot targeting New York synagogues. (AP Photo/Louis Lanzano) | AP

NEW YORK — A man charged with participating in a plot to blow up synagogues is a proud American and the case against him is questionable, his lawyer said Tuesday as prosecutors announced the indictment of a second suspect accused of playing a more prominent role in the alleged scheme.

Ahmed Ferhani, a 26-year-old Algerian, and Mohamed Mamdouh, a 20-year-old U.S. citizen of Moroccan descent, were arraigned last week on initial charges including conspiracy as a crime of terrorism, a rarely-used state law. Both deny the allegations.

Ferhani was arrested buying guns, ammunition and an inert grenade in a sting on a Manhattan street last Wednesday, and Mamdouh was picked up soon afterward, the Manhattan district attorney's office said. An undercover detective had secretly recorded both men ranting about their hatred of Jews and discussing a synagogue attack, according to prosecutors.

Ferhani has been indicted, prosecutors said Tuesday, though they didn't immediately disclose what charges the grand jury found appropriate. The indictment will likely be released at a June 16 court date.

Mamdouh appeared separately as his lawyer agreed Tuesday to give prosecutors until June 2 to take the case against the Casablanca-born taxi dispatcher to a grand jury. Meanwhile, attorney Aaron Mysliwiec underscored that Mamdouh is "proud to be an American citizen" and noted news reports saying that some in the FBI, which didn't participate in the case, had questions about how much proof there was in the case.

"We look forward to raising those same questions. And we look forward to fighting these charges in the courtroom," Mysliwiec said outside court.

Police said the FBI was made aware of the investigation but decided not to get involved. The FBI, the Department of Justice and federal prosecutors in Manhattan declined to comment. But a law enforcement official briefed on the case, who wasn't authorized to speak publicly and spoke on condition of anonymity, told The Associated Press last week that the FBI had reservations about how the probe was conducted and concluded it "wasn't a legitimate terrorism case."

Ferhani and Mamdouh, who lived blocks away from each other in Queens, are being held without bail. Each could face life in prison if convicted.

Ferhani is in good spirits under the circumstances, said his lawyer, Stephen Pokart.

Ferhani, who is unemployed, moved to the U.S. in 1995 from war-torn Algeria with his parents and claimed asylum, authorities said. He had been granted permanent resident status but is facing deportation.

Mamdouh and his family came to the U.S. in 1999, officials said. His parents are now local business owners, a prior attorney said.

Angry about how he felt Muslims have been treated around the world, Ferhani made ever more ambitious terror plans during the seven-month investigation, prosecutors said. He eventually suggested disguising himself as an observant Jew so he could infiltrate a synagogue and leave a bomb inside, according to a court complaint.

After meeting the undercover officer, Ferhani brought Mamdouh into their discussions, authorities said. On May 5, the undercover detective introduced the men to another officer pretending to be an illegal gun dealer, the court complaint said.

There was no indication the alleged plot ever put New Yorkers in danger and no evidence the men were affiliated with any terrorist organization.